A woman waits at a polio immunisation health centre, in Maiduguri, Borno State, Nigeria, August 29, 2016. Nigeria's military has liberated large swathes of land from Boko Haram but a ride with an army convoy, all guns firing for fear of ambush, shows how far the northeast is from normality after a brutal Islamist insurgency that has displaced millions. (Photo by Afolabi Sotunde/Reuters)

Paramedics carry an injured woman out from a subway station after a rush-hour subway train derailment, to be transported by a medical helicopter in Moscow, Russia, on Tuesday, July 15, 2014. A rush-hour subway train derailed in Moscow Tuesday, killing 20 people and injuring at least 150, emergency officials said. Several cars left the track in the tunnel after a power surge triggered an alarm, which caused the train to stop abruptly. (Photo by Ivan Sekretarev/AP Photo)

Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

NEPAL: A devotee is smeared with a vermillion powder while celebrating the “Sindoor Jatra” vermillion powder festival at Thimi, in Bhaktapur, Nepal, April 14, 2016. (Photo by Navesh Chitrakar/Reuters)

Carolina Gutierrez (center L), 17, and Neuil Valdez, 18, use mobile phones to connect to the internet at a hotspot in downtown Havana, Cuba, December 12, 2016. (Photo by Alexandre Meneghini/Reuters)

Argentinian dancer Maria Belen Ciaschi, stranded in Lebanon due to COVID-19 coronavirus pandemic, dances flamenco to the music played by Uruguayan singer Walter Javier Maulelo while both wearing a mask on a seafront boardwalk in the northern coastal city of Batroun, on April 15, 2020. (Photo by Ibrahim Chalhoub/AFP Photo)

Natalie Duran, wearing a mask and dressed as Catwoman, climbs on street lights in SoHo as the city continues Phase 4 of re-opening following restrictions imposed to slow the spread of coronavirus on July 25, 2020 in New York City. The fourth phase allows outdoor arts and entertainment, sporting events without fans and media production. (Photo by Alexi Rosenfeld/Getty Images)

A woman sells chips in Abidjan, Ivory Coast on August 09, 2019. World's number one cacao producer Ivory Coast's capital Abidjan set peace after the 201011 Ivorian crisis. Women in Abidjan work in various jobs to help their families' budget. (Photo by Mahmut Serdar Alakus/Anadolu Agency via Getty Images)